The present invention relates to a method and device for inputting/detecting the coordinate position and a display board system and more particularly, to a method and device for enabling input and/or detection of coordinates of not only a two-dimensional position but also a three-dimensional position with improved operability as well as a display board system which uses the coordinate-position inputting/detecting device.
Conventionally there has been known a display board which can read freehand information written on a whiteboard or on a writing surface of a writing sheet with some writing tool using a dedicated scanner and output the read information onto a recording paper with a dedicated printer. While, in recent years, there has also been suggested a display board system in which a coordinate-position inputting/detecting device is provided in a writing surface of a display board for enabling inputting of freehand information written in the writing surface in real time.
For instance, the Soft Board manufactured and provided by the Microfield Graphics, Inc. is a device having a coordinate-position inputting/detecting device provided on a whiteboard. This Soft Board can acquire visual data such as characters and pictures drawn on the whiteboard into a computer in real time. With the display board system using this Soft Board, it is possible to input visual data captured with the Soft Board into a computer for displaying the data on a CRT thereof. The data may be displayed on a large-sized screen using a liquid crystal projector, or the data may be printed on a recording paper using a printer. It is also possible to project an image on a screen of a computer with the Soft Board connected thereto onto the Soft Board with a liquid crystal projector and operate the computer on the screen of the Soft Board.
There has also been disclosed a display board system having a display unit for displaying characters and images thereon, a coordinate-position inputting/detecting device with a coordinate-position input surface (a touch screen) provided on a front surface of the display unit, and a control unit for providing controls over display by the display unit according to input from the coordinate-position inputting/detecting device. This system forms a display surface and a writing surface of the display board by making use of the display unit and the coordinate-position inputting/detecting device.
For instance, in case of the Smart 2000 manufactured and supplied by the SMART Technologies Inc., when an image of a character, a picture, or a graphics is projected with a liquid crystal projector connected to a computer onto a panel, freehand information is captured into the computer using a coordinate-position inputting/detecting device (writing surface) provided on a front surface of the projection surface (display surface) of the panel. Then, the freehand information is synthesized with the image information in the computer, and the synthesized information can be displayed again with the liquid crystal projector in real time.
The display board system can display an image inputted by the coordinate-position inputting/detecting device that is superimposed on an image on the screen displayed by the display unit as an overwritten. Because of this characteristics, this display board system has been used in conferences, presentations, or for educational purposes and its effect in actual use has been highly evaluated. When a communicating function for transferring audio or video data is integrated with the display board system as described above, the display board system can also be used as an electronic conference system by connecting remote sites with a communication line.
By the way, as a coordinate-position inputting/detecting device used in the display board system as described above, devices described below are known according to a difference between input methods thereof. As a first case, there is an optical coordinate-position inputting/detecting device disclosed in Japanese Patent Laid-Open Publication No. HEI 8-240407. This coordinate-position inputting/detecting device has two infrared CCD cameras and these cameras detect a peak signal of an infrared ray from the infrared LED provided on a pen-type pointing body inserted in a coordinate-position entry area with the infrared CCD camera to compute a coordinate position pointed by the pointing body.
As a second case, there is an optical coordinate-position inputting/detecting device disclosed in Japanese Patent Laid-Open Publication No. HEI 9-319501. In this coordinate-position inputting/detecting device, the coordinate entry area is scanned with a laser beam. A pen pen-type pointing body with a corner cube reflector as a recursive reflecting member provided thereon is inserted into the coordinate entry area and an arbitrary position is pointed thereby. Light is recursively reflected by the pointing body. The reflected light is received by a plurality of light-receiving elements and a position pointed by the pointing body is computed.
With the coordinate-position inputting/detecting device in the above mentioned case, however, as a dedicated pointing body is required for pointing to an arbitrary position in the coordinate entry area, an input operation with, for example, a fingertip, is not allowed, which is inconvenient. Furthermore, when the dedicated pointing body is lost or damaged, the input operation using the coordinate-position inputting/detecting device can not be carried out. On the other hand, in the coordinate-position inputting/detecting device in the first case, an infrared LED has to be provided in a pointing body, therefore, power unit or so for the pointing body is required, which is inconvenient from the view point of its maintenance.
Furthermore, in the coordinate-position inputting/detecting device, coordinates of only a two-dimensional (X-Y direction) position can be inputted, therefore, it is difficult to determine movement of a pointing body in the vertical direction (Z direction) and a double click or the like.
It is an object of the present invention to improve, for the purpose of solving the problems described above, operability and usability of a method and device for inputting/detecting the coordinate position by enabling specification of coordinates of a position in an entry area pointed thereto with an arbitrary pointing body such as a fingertip or an ordinary pen without using a particular pointing device.
It is another object of the present invention to realize a coordinate-position inputting/detecting device enabling entry of not only a two-dimensional position but also a three-dimensional position.
It is another object of the present invention to improve workability and adaptability to handling of a display board system by using the coordinate-position inputting/detecting device with excellent operability.
In the present invention, an image of a pointing body inserted into an entry area is picked up by at least two image pickup elements. Then, the position of the image of the pointing body formed on each of the image pickup elements is obtained according to the output from each of the image pickup elements. Finally, coordinates of the position of the pointing body are identified by using the computed positions of the images. Therefore, entry operation can be carried out using an arbitrary pointing body without using a particular pointing body.
In the present invention, light is emitted from light emitting unit into the entry area. An image of a pointing body illuminated by the light emitted from the light emitting unit is picked up by at least two image pickup elements. Then, the position of the image of the pointing body formed on each of the image pickup elements is obtained according to the output from each of the image pickup elements. Finally, coordinates of the position of the pointing body are identified by using the computed positions of the images. Therefore, an entry operation can be carried out using an arbitrary pointing body without using a particular pointing body.
In the present invention, the light emitting unit and the image pickup devices are so placed that the direction of the light emitted from the light emitting units is substantially the same as the direction from which the pointing body is viewed from each of the image pickup elements. Therefore, the light emitted from the light emitting unit does not directly enter the image pickup elements, and also shadow is not generated on the pointing body as much as possible.
In the present invention, there is provided an incident light preventing unit for preventing the light emitted from the light emitting unit from directly entering into each of the image pickup elements. Therefore, the light emitted from the light emitting means does not directly enter into the image pickup elements.
In the present invention, the light emitting unit comprises at least a light source and a mirror. Therefore, the light emitted by the light source can be reflected by the mirror and diffused along the entry area, so that, a light that covers the entire entry area can be emitted from the light emitting unit.
In the present invention, the angle of the light emitted by the light source can be changed by operating the mirror, so that, direction in which the light is reflected from the mirror can be adjusted.
In the present invention, light reflected by a mirror is received by a light receiving element, and the angle of the mirror is changed according to intensity of the light received by the light receiving element.
In the present invention, there is provided a reflection preventing unit which prevents the light emitted by the light emitting unit from its being reflected, so that unnecessary light does not enter the image pickup elements.
In the present invention, when coordinates of the same position are obtained continuously then it is determined that the coordinates are obtained due to dust or something. In such a case the coordinates of this position are not stored in the memory and also are not outputted to an external device. As a result, it is possible to prevent coordinates of the position obtained due to dust or something from its being outputted to an external device.
In the present invention, optical distortion of an image of a pointing body picked up by each of image pickup elements is electrically corrected, and higher quality of an image of a pointing body can be obtained.
In the present invention, when a plurality of pointing bodies each with a different pattern provided thereto are inserted into the entry area, patterns are recognized according to each output from the image pickup elements, which allows an entry operation concurrently using the plurality of pointing bodies to be carried out.
In the present invention, width of the pointing body is determined according to images of the pointing body picked up by image pickup elements.
In the present invention, the coordinates of the position of a pointing body identified by coordinate-value identifying unit is corrected by using the width of the pointing body obtained by the width identifying unit so that it is possible to obtain coordinates of an accurate position.
In the present invention, image of an entry area previously picked up by each of image pickup elements is stored as a reference image, images of the entry area picked up afterward by each of the image pickup elements are extracted. Then, a difference between the corresponding reference images and images of the pointing body inserted into the entry area obtained by the corresponding image pickup elements is extracted. From this difference, a position in the image of each of the image pickup elements where an image of the pointing body is formed is computed and coordinates of the position of the pointing body are obtained using the computed positions of the pointing body.
In the present invention, image of the entry area is picked up utilizing two-dimensional image pickup elements, which allows coordinates of a three-dimensional position of a pointing body to be computed.
In the present invention, a reference image consists of an image only of a background plate, so that an image of only a pointing body can easily be extracted from an image with the background plate and the pointing body included therein.
In the present invention, image of the pointing body can easily be extracted just by removing a reference pattern from an image in which the background plate and the pointing body is present.
In the present invention, an area photographable by the image pickup element is restricted by an area restricting unit so that the area is adjusted to the entry area. Therefore, the image pickup element may not be affected by noise such as interference light.
In the present invention, when coordinates of the same position are obtained continuously then it is determined that the coordinates are obtained due to dust or something. In such a case the coordinates of this position are not stored in the memory and also are not outputted to an external device. As a result, it is possible to prevent coordinates of the position obtained due to dust or something from its being outputted to an external device.
In the present invention, by deciding each image of an entry area used to compute coordinates of a position abandoned by updating means as each new reference image, dust existing on the entry area is taken in as a portion of a reference image. Therefore, it is prevented that coordinates of a position of dust are disadvantageously computed.
In the present invention, a coordinate-position inputting/detecting device is provided in the front surface of a display unit for displaying characters and images, and a display surface and a writing surface of a display board are formed with the display unit and coordinate-position inputting/detecting device, so that viewability of the display unit and operability of the system can be improved.
In the present invention, a coordinate-position inputting/detecting device is provided in the front surface of a display unit for displaying thereon characters and images. As a result, a display surface and a writing surface of the display board are formed with the display unit and coordinate-position inputting/detecting device, so that viewability of the display unit and operability of the system can be improved. Furthermore, the display board system comprises a frame unit having a holding section for holding a display surface and a writing surface of the display board at a specified height, a printer accommodating section for accommodating the printer therein, and a control unit accommodating section for accommodating the control unit therein. The control unit accommodating section, printer accommodating section and the holding section are arranged in the vertical direction in this order from the bottom. As a result, transport and installation of the system can easily be carried out.
In the present invention, by using a plasma display as a display unit, optimization of the display board system can be performed. Namely, use of the plasma display allows the thickness of a display unit to be reduced, and the plasma display also has high brightness as well as a wide viewing angle, and can reproduce moving pictures smoothly, so that the plasma display is preferable as a display unit of the display board system.
In the present invention, a keyboard placement section for placing a keyboard connected to a personal computer is provided at a position in the upper side of the printer accommodating section and in the lower side of the holding section. Therefore, handling capability of the system is improved.
In the present invention, an angle adjusting unit for adjusting an angle of a display surface and a writing surface of the display board is provided in a holding section. Therefore, disturbance light coming into the display unit (display surface), especially, light from lighting equipment such as a fluorescent tube on the ceiling can be prevented.
In the present invention, a plurality of connecting terminals for connecting various types of information equipment and AV equipment such as a digital camera, a DVD player, and video equipment are provided in a display unit and is usable as a large-sized screen monitor. Therefore, the display board system can be used in any occasion.
Other objects and features of this invention will become understood from the following description with reference to the accompanying drawings.